This workshop service manual covers the Mercury Mariner DFI Optimax Series outboard engines manufactured between 2000 and 2005. These 2-stroke DFI Optimax outboards, with a displacement of 1.5 liters and producing 115 HP, are engineered for reliable performance on the water. Featuring advanced Direct Fuel Injection (DFI) technology and a water-cooled system, these engines are designed to provide efficient power for a variety of marine applications. The robust construction and thoughtful engineering of the Mercury Mariner series ensure durability and a consistent operational experience. The purpose of this manual is to provide comprehensive guidance for the repair and overhaul of your Mercury Mariner outboard. It details essential maintenance procedures, troubleshooting steps, and technical specifications necessary for optimal engine function. Owners, mechanics, and technicians will find detailed information on lubrication, service schedules, electrical and fuel systems, cooling, and propulsion. Adhering to the procedures and recommendations within this manual will help ensure the longevity, performance, and safety of your Mercury Mariner engine.